Force measuring platforms, which are primarily designed to measure the location of the center of pressure, and mainly used in balance assessment and related fields, are generally known as balance plates. As a typical subject tested on a balance plate has a balance disorder or a potential balance problem, it is important that subjects can easily step on and off a balance plate. Therefore, it is very desirable that balance plates have as low a profile as possible. A further desirable characteristic of a balance plate is its portability. Therefore, it should be light weight, and house the associated electronics within the plate itself.
The measurement technology of the prior art does not accomplish the above desirable characteristics. The prior designs utilize pin-wheel measurement devices with cross-beams inside the wheel, or four or more load cells to measure forces, or piezoelectric technology, or elaborate systems of machined beams and plates, or the combination of measuring plates, or utilizing a platform with rockers underneath. Most are incapable of measuring both forces and moments. These past designs were bulky and cumbersome making them difficult to get on and off of, as well as difficult to transport.
The purpose of the disclosed invention is to provide the means for analyzing and measuring the balance, functional capability, and stability of a subject or load. The present invention is directed to a balance analysis system that satisfies the measurement capabilities, low profile, and portability needs identified in the BACKGROUND section above.
This object is accomplished by disclosing a balance plate (or xe2x80x9cplatformxe2x80x9d) system FIG. 1 capable of measuring all force and moment components and calculating the location of the center of pressure of the subject or load. Other versions of the invention measure the force components at each corner of the plate and calculate the center of pressure. Internally, the plate is comprised of two or more beams FIG. 3 and FIG. 3A with two or more strain gages geometrically affixed to each beam FIG. 4 allowing for the measurement of up to six force and moment components. The beams and gages are enclosed in a light-weight, portable, and level-adjustable housing structure which has a low profile for ease of load placement and accessibility by a human or animal subject for stepping onto and off of the plate FIG. 2. Within the plate is the necessary technology for data collection and transmission; including, signal amplification device(s) and signal transmission device(s) FIG. 5. For analysis, display, and interpretation of the data collected by the plate, a data collection device and the necessary hardware and software therefore are employed FIG. 1; including, data acquisition device(s) (e.g., computers, desk-top or lap-top versions utilizing monitors and printers, and data acquisition cards), as well as computer program(s) for analysis, display, interpretation of the data, and user interaction with the system.
When used to analyze a subject, an optional support structure FIG. 10 with an adjustable harness FIG. 11 can be employed to ensure safety, and allow for a greater range of measurement during sway and perturbance tests. The perturbance tests can be performed with a pad made of compressible material as disclosed herein FIG. 9.
This device and system has multiple applications in the biomechanical and medical fields; including, but not limited to, the measuring and testing of a subject""s balance, coordination, gait, movement, posture, stability and instability, and sway. Generally, versions of this invention will be used to test for the existence of balance problems in a subject or the likelihood of a balance problem, as well as the magnitude of the problem, and aid in the determination of the cause; whether the cause is inner ear, muscular, neurological, ocular, skeletal related, or otherwise. The disclosed plates are sensitive enough to measure the tremor(s) in patients, and then using an algorithm the data collected is viewed in the frequency domain to reveal the potential ability to decipher such things as the stage of Multiple Sclerosis, and the efficacy of drug dosages for Parkinson""s disease.
Because up to six degrees of freedom can be measured, there are many applications beyond the general-clinical measuring and testing. For example, this device and system can measure and test for the effects and impairments of drugs (e.g., alcohol) on a subject""s capability to function. Likewise, this system can be employed to measure an athlete""s functional capability prior to, during, or after activity, or to measure the subject""s capability to return to the activity after an injury.
Therefore, the presently disclosed balance analysis system improves upon the prior art and provides for the means of measuring and testing a subject""s balance neither contemplated nor demonstrated by the prior art.